The 26-year-old Gausman tweeted that growing up in Colorado he became a fan of Halladay, a fellow Colorado native, and decided that part of remembering him would be to wear his number. He had been wearing No. 39 since 2014.

Halladay, a two-time Cy Young winner, died on Nov. 7 when his single-engine plane crashed in the Gulf of Mexico. He was 40 years old.

Halladay wore No. 34 in his four years with the Philadelphia Phillies. Before then, the wore No. 32 in parts of 12 seasons with Toronto Blue Jays.

Gausman is 34-43 with a 4.18 ERA in his five seasons with the Orioles. He is projected to be the team's No. 2 starter.

Gausman's announcement via Twitter:

"Being a kid in love with the game of baseball, many of my afternoons and fondest childhood memories are of watching the game with my dad," Gausman wrote in a Twitter note. "Naturally, I became a huge fan of fellow Colorado native Roy Halladay. He instantly became my idol. For years I watched him dominate his competition. To me, Roy gave me the inspiration that I could fulfill even my biggest of dreams – being a pitcher just like him. The older I got the more I began to understand the challenges of being a baseball player in Colorado. There have been less than 100 Major League Baseball players that were born there. I'd like to think we have our own fraternity amongst ourselves. The loss of Roy was tragic and is saddening, but I feel honored to have watched everything he achieved. I plan to wear #34 next season to honor Roy Halladay both on and off the field."